A connection between flavour anomaly, neutrino mass, and axion

Journal of High Energy Physics

Seungwon Baek¹ 

[1] Department of Physics, Korea University, Anam-ro 145, Sungbuk-gu, 02841, Seoul, Korea;

关键词: Beyond Standard Model;    Gauge Symmetry;    Global Symmetries;    Heavy Quark Physics;   

DOI  :  10.1007/JHEP10(2020)111

来源: Springer

【 摘 要 】

We propose a minimal model in which the flavour anomaly in the b → sμ+μ− transition is connected to the breaking of Peccei-Quinn (PQ) symmetry. The flavour anomaly is explained from new physics contribution by introducing one generation of heavy quark and heavy lepton which are vector-like under the standard model (SM) gauge group but charged under a local U(1)X group. They mix with the SM quarks and leptons, inducing flavour-changing Z′ couplings, which generates the b → sμ+μ− anomaly at tree level. On the other hand the new fermions are chiral under the global Peccei-Quinn(PQ) symmetry. The pseudo-Goldstone boson coming from the spontaneous breaking of the PQ symmetry becomes an axion, solving the strong CP problem and providing a cold dark matter candidate. The same symmetry prevents the right-handed neutrino from having a Majorana mass term. But the introduction of a neutrino-specific Higgs doublet allows neutrino to have Dirac mass term without fine-tuning problem. The model shows an interplay between axion, neutrino, dark matter, and flavour physics.

【 授权许可】

CC BY